1. Field of the Invention
The present invention is broadly concerned with improved oxygen delivery units particularly designed for emergency use by commercial aircraft passengers. More particularly, the invention pertains to such oxygen delivery units utilizing exothermic oxygen generators wherein the oxygen generator is shiftably mounted within a housing to increase the distance between the generator and the housing when the generator is activated. In preferred forms the generator is attached to a flexible release plate and held in a stored position by a release lanyard assembly. When the release lanyard assembly is separated, the release plate uncurls shifting the generator downwardly and away from the housing.
2. Description of Prior Art
Pyrotechnic charges, commonly referred to as candles, are operative to generate single gases for a variety of purposes. For example, oxygen candles, which generally employ sodium chlorate or potassium perchlorate, are commercially available where an ordinary air supply might be limited or contaminated. These candles operate at temperatures in excess of 500.degree. F. (260.degree. C.). These devices are typically held in a housing and supply oxygen to an individual through a mask.
Oxygen candles are commonly used in commercial passenger aircraft as oxygen generators to provide a supplemental supply of oxygen in certain emergency situations, e.g., after a drop in cabin pressure at high altitude. Most candles currently in use operate for up to 15 minutes. However, a recent increase in the desired operation time to twenty-two (22) minutes requires larger candles that burn at increased temperatures. These candles are typically held in the housings of oxygen delivery units which are typically positioned above the passengers and underneath the overhead stow bin compartments. In this area, the enlarged oxygen candles and their corresponding masks must be juxtaposed to the housing walls because there is not enough space to separate the candles from the housing walls. The excessive heat generated by the candles can damage the housings, surrounding structures or luggage and more critically can ignite the housings, surrounding structures, or luggage starting a fire on the aircraft.
In order to utilize the larger oxygen candles, some oxygen generator units utilize various mechanisms to shift the oxygen candles away from the housings when the candles are activated. For example, British Patent No. 2,111,837 discloses a slide to shift the generator, and U.S. Pat. No. 5,301,665 discloses a related approach in which the generator pivots to shift it away from the housing. These units are capable of spacing the candles away from the housings, so that the housings, surrounding structures, and luggage are not damaged or ignited by the candles. It is essential that these mechanisms reliably shift the candles away from the housings to inhibit damage and fires. However, these known mechanisms and others are overly complex thereby inhibiting their reliability and unduly increasing their cost. Further, these systems occupy inordinate amounts of space.